Manufacture of detergents.



UNITED s ATEs PATENT OFFICE.-

WILLIAM REGINALD ORMANDY AND .mcos WILLIAM SPENSLEY, or MANCHESTER,

ENGLAND.

MASNUFACTURE OF DETERGENTS.

\ Specification of Letters Patent. Patented Aug. 20, 1912- "A lication filed March a, 1912. Serial No. 682,672.

To all whom it may concern Be it known. that we, \VILLLUI Rcoixam Ommnor and Jaco'n lVnlLn-nt, Srnxsrm', subjects of the King of Great- Britain, both residing at Manehcster, in the county of Lancaster, in the Kingdom of England, have invcntecYcertain new and useful 11n grovemcnts Relating to the Manufacture of etergents, of which the following is a specification.

This invention relates to the manufacture of washing compositions or detergents;

It is the object of the invention to produce a washing composition which can be sold ina finely divided form and which will have practically no tendency to cake or solidify when kept for some time before use,

in paper bags for instance.

The invention relates part-icularl to the manufacture of finely divided washing sodas which may consist either of carbonate of soda alone or more usually of mixtures of carbonate with silicate of -soda. or with other detergent substances of a similar characrcs; i \Ve have found experimentally that such washing sodas as hitherto made contain mixtures of carbonates with various amounts of water of crystallization, and it, is mainly the subsequent; exchange of water-from the carbonate with most water to' the carbonate with lesser amounts of water of crystallization,-and the consequent growth of fresh crystals, which causes the binding together of the mass into a hard ,cake or lump.

The present invention is based on the discovery that. if finely divided washing soda containing the mixed carbonates be heated to a certain teuwerature and stirred or agitated continuously, the exchange of water of crystallization can be caused to take place rapidly. producing a washing soda containing carbonate which is practically all uniformly hydrated. The temperature in question is that at which the washing soda just. begins to sol'tcn, and it must notbe so high that the mixture changes into a. liquid form. The action which takes place may be explaincd as follows:-If a solution of sodium carbonate in warm water be cooled down, it is found that there is a range of temperatures between about 34 degrees and 30 de grees centigrade within which the carbonate crystallizes out with 7 molecules of water of crystallization (Na. .CO,,7H. .O). Below the temperature of 30 degrees however the carbonate which crystallizes out from a solution or mixture with water is the'decahydrated carbonates (Na cOaIoH O). The critical temperature below which the decahydrated carbonate forms is lower than 30 degrees when other substances such as silicate of soda are present in the mixture, and for instance ifi .sili ate of soda solution of 1.2 specific gravity, be mixed with an equal amount by weight; of anhydrous carbonate of soda, (so thatthe mixture contains about 19 parts by weight of silicate of soda to 100 parts of carbonate and 100 parts, of water), the critical temperature below which .the decahydrated carbonate begins to form is about fl -dcgrces centigrade, instead of 30 degrees as stated above for the carbonate mixed with water alone. It may be even lower when a larger proportion ofsilicate is present. "The washing sodas usually made contain sodium carbonate mainly in the form of the decahydrated and the monohydrated carbonates. The object of the heating according to the present invention is to produce apractically uniformly Lhy' drated carbonate as already stated. It the mixture were heated sufiiciently to turn it into a liquid it would be necessary to 'eon-.

tinue the heating for some time to make the 5 whole mass liquid at a temperature above .the range already referred to and then to allow crystallization to take place within' this range. .If however the mixture be heated until it just begins to soften, a little below the critical tempe 'ature for the formation of the decahydrated carbonate above referred to, the. whole of the highly hydrated carbonate is brought. into a condition in which it is very ready to give up some of its water, that is to say its vapor tension is very high. The vapor tension of the monohydrated carbonate present is still very low. lonscquently the .water from the decah'ydrated carbonate is readily t'ansl crrcd to the monohydratcd carbonate present, while the whole mixture is kept well stirred or agltated at; the deslred temperature. There 18 no necessity to determine together. The resulting product wi l 15 ally contain the. whole of the carbonate in accurately in advance the-critical temperature for the formation of the decahydrated .carbonate, but the mixture of materials canbe heated as before mentioned until the crystals begin to soften and this determines the temperature which must be ex-.

not escape, and the vessel must be fitted with a stirring apparatus to keep the mixture well. agitated and to prevent new crystals from growing so as to bind the articles generthe condition of penta-, hexa-" or heptahydrated carbonate according to the amount of water originally present in the mixture. If there is insuificient'water present some may be added, preferably'in the form of more hexa-liydrated carbonate, and if too much water present some may be removed by carrying out the operation for instance in an apparatus connected to asuction plant as described hereinafter, so as to evaporate some of the water. The'result-ing carbonates with the amounts of water \of crystallization above mentioned, do not tend to give up or absorb water to any appreciable extent, and the resulting mixture therefore has cakeor solidify.

The operation above referred to may be conveniently carried into effect in a mixing practically no tendency to apparatus of the type shown in the drawmgs. In this apparatus a represents the frame, 6 is a water inlet and 0 a water outlet communicating with a water-jacket, d.

Water heated't-o any desired temperature 40 may be thus.supplied to the jacket 03 in order to keep' the substances inside the apparatus at any desired temperature. The mixing blades e indicated in dotted lines are on a shaft or shafts driven from a pulley f through gearing g- A pipe I leading from the top of the apparatus may communicate with a vacuum pump 70 which may be used to draw off some of the water vapor from the mixture as stated if rather too muchwater is present in the mixture. Of

course any other convenient form of mixing apparatus could be used for. the purpose, and the apparatus illustrated is intended to serve as an example only.'

It will be clearly understood that the process according to the present invention is applicable for use in producing finely divided washing sodas-which will not tend to cake from washing sodas already produced but which have become caked, or are in a condition' to become caked, the caked masses 'being broken up if required before the mixture is subjected to the process according to this invention. The process may obviously be applied also to the treatment of mixtures constituting washing sodas directly they are produced by crystallization from a solution.

l/Ve declare that what we claim is 1. A process for manufacturing washing soda in a finely divided form, consisting in heating a detergent mixture containing finely divided carbonate of soda with various amounts of water of crystallization, to a temperature just below. the critical temperature at which the decahydrated carbonate begins to form from a solution containing the same materials which is being cooled down from a higher temperature, stirring the mixture while maintaining it at the said temperature just below the critical temperature mentioned until the water of crys 'tallization has become transferred from the more highly hydrated carbonate to that with less water of crystallization, whereby a i just begins to soften, but does not actually liquefy, whereby the vapor tension of the carbonate with the highest amount of water of crystallization is greatly increased, and a transfer of water is caused to take place until a practically uniformly hydrated carbonate with an intermediate amount of water of crystallization is produced.

'3. A process for manufacturing washing soda in a finely divided form, consisting in stirring a mixture of silicate and carbonate of soda in the form ofcrystals with various amounts (if water of crystallization, the stirring being continued at a temperature just below that at which the mixture begins to become li uid, until the water of crystal- -soda of a consistency such that it tends to crystalliza- A amounts of become caked when kept, the process consisting in stirring afdetergent mixture containing finely divlded washing soda. 1n a form which tends to cake, and maintaining the temperature of the mixture at a point such that the mixture just begins to soften 1912, iii the presence of two subscribing Without actually liquefying, until the resultwitnesses. ing, mixture contains carbonate of soda in a condition in which it is all crystallized with 5 from 5 to 7 molecules of Waterofcrystallization. Witnesses In witness whereof, we have hereunto RICI-ID. L. Grin-wan, signedour names this 26th day of February H unnu'r A. GILL.

WILLIAM REGINALD ORMANDY. JACOB WILLIAM SPBNSLEY. 

